The disclosed embodiments of the present invention relate to a feedthrough signal transmission circuit and method, and more particularly, to a feedthrough signal transmission circuit and method utilizing at least one permanently on buffer and a switchable normal buffer which can be selectively powered off.
A feedthrough is a conductor used to carry a signal through a printed circuit board (PCB). Feedthroughs can be divided into power and instrumentation categories, wherein power feedthroughs are used to carry either high current or high voltage, and instrumentation feedthroughs are used to carry electrical signals which are normally low current or voltage.
Please refer to FIG. 1, which shows a feedthrough in a circuit design according to the related art. As shown in FIG. 1, the circuitry 100 comprises three circuits 10, 20, 30 belonging to different partition/block/power domains. When the circuit 20 transmits signals to the circuit 10 or receives signals from the circuit 10, those signals have to go through the circuit 30 between the circuits 10 and 20. For this reason, the circuit 30 has to be designed as a permanently on type; otherwise, the signal transmission between the circuits 10 and 20 may fail. If the circuit 30 were powered off, the circuit 20 would not be able to transmit signals to the circuit 10 or receive signals from the circuit 10. Using a permanently on cell, however, will raise the power consumption. Specifically, when a source block preceding the feedthrough circuit and a sink block following the feedthrough circuit are powered down, the feedthrough circuit will remain powered on, which inevitably results in leakage power. Therefore, there is a need for a novel feedthrough design which uses a permanently on cell but wherein the circuit can be powered off.